The longevity of mobile device's battery is nowadays of vital importance since the complexity and functionalities of mobile devices increase all the time and the requirements for the enabling hardware increases at the same pace. It is not uncommon to a modern mobile device that there are a number of applications running simultaneously, each application having possibly several threads running, using various system functions such as networking stack and other services.
Web applications today are more elaborate than ever. Web 3.0 concepts, such as widgets, are coming more and more popular, providing users new never-seen-before possibilities to use and control the services they use daily. The term widget refers to a piece of code for a stand-alone application that an end user can install and execute within any separate HTML-based (HyperText Markup Language) web page without requiring additional compilation. For example, various on-screen tools, like clocks, daily weather forecasts and stock market tickers, are typically implemented as widgets.
In general, it can be seen that the development of Web applications is currently guided towards the tendency, where the actions user makes are handled through an event-based approach model. In practice, a web application is a collection of active and passive components, which react to events user initiates via user interface or alternatively another application or sub-application initiates without user interaction.
Power management, in general, has been of interest already for several actors in consumer product industry area. Particularly, within the field of mobile devices several solution have been provided, which concentrate e.g. on radio frequency interface monitoring, energy consumption of a network service or refraining from downloading a web resource. However, none of them provides a reasonable basis for an energy consumption optimisation in an application environment, where widgets and other event-based applications are run continuously in the background.